3-Axis accelerometer and strain sensor readout for MEMS-based capacitive sensors

A low-power capacitive readout for MEMS-based strain sensors and accelerometers is presented. A novel technique to optimise the trade-off between gain, bandwidth and noise is introduced. The readout can work with both types of sensors in the range of ±2.5g and ±20,000 μe. Artefact cancellation such as residual motion is suppressed due to accurate control of the 3dB point in the built-in filter of the architecture. A figure of merit of 4.41×10 F√(W/Hz) was achieved. The ASIC was developed using a 0.25μm CMOS technology.